Bounce rate is the percentage of sent emails that could not be delivered to the recipient.
In depth
Bounces split into hard bounces, which are permanent failures, and soft bounces, which are temporary. A high bounce rate hurts sender reputation and deliverability, so keep it low; under about 2 percent is a common target. Causes include invalid addresses, full mailboxes and server issues. Use double opt-in, validate addresses at signup and remove hard-bouncing addresses immediately.
Example
If 10,000 emails are sent and 150 bounce, the bounce rate is 1.5 percent.
Related terms
See our full email marketing glossary or the complete email marketing guide.